Published surveys show that no less than one in ten adult Americans takes a benzodiazepine tranquilizer or hypnotic in a year's time. These compounds are prescribed to treat a wide variety of conditions, for example, neurotic anxiety, depression, insomnia, muscle spasm, and countless functional disorders ranging from headaches to dyspareunia. (Benzodiazepines in Clinical Medicine, Greenblatt and Shader, Raven Press, 1974, v).
After therapeutic doses of benzodiazepines, only trace amounts are present in body fluids due to extensive biotransformation and tissue distribution. Therefore, very sensitive methods are needed to enable quantitation of benzodiazepines in tissue and body fluids.
A variety of screening procedures exist for the detection of benzodiazepines in blood, urine, or body fluids. Thin layer chromatography (TLC) or gas liquid chromatography (GLC) or spectrophotofluorometry have been used. More recently immunoassays utilizing antibodies to benzodiazepines have been developed and have proved to be very effective in quantitating minute amounts of benzodiazepines in body fluids. In this technology it is particularly necessary to have a compound which acts as a substrate upon which the "tracer" (which enables detection and quantitation of the unknown analyte) may bind. Various benzodiazepine derivatives have been used for this purpose. See U.S. Pat. No. 4,083,948 by Davis et al. which describes Benzodiazepine Radioimmunoassays Using I.sup.125 Labels attached to benzodiazepine derivative substrate molecules.